Wireless communication networks are widely deployed to provide various communication services such as voice, video, packet data, messaging, broadcast, etc. These wireless networks may be multiple-access networks capable of supporting multiple users by sharing the available network resources. Examples of such multiple-access networks include Code Division Multiple Access (CDMA) networks, Time Division Multiple Access (TDMA) networks, Frequency Division Multiple Access (FDMA) networks, Orthogonal FDMA (OFDMA) networks, and Single-Carrier FDMA (SC-FDMA) networks.
A wireless communication network may include a number of base stations (e.g., eNodeBs) that can support communication for a number of user equipments (UEs). A UE may communicate with a base station via the downlink and uplink. The downlink (or forward link) refers to the communication link from the base station to the UE, and the uplink (or reverse link) refers to the communication link from the UE to the base station.
Additionally, UEs can be equipped to communicate in wireless local area networks (WLAN) by accessing one or more hotspots using a wireless communication technology, such as Institute of Electrical and Electronics Engineers (IEEE) 802.11 (WiFi). In this regard, a UE can communicate with a radio access network (RAN) of a wireless wide area network (WWAN) (e.g., a cellular network) along with a RAN of one or more WLANs. The UE can include a transceiver operable for communicating with the RAN of the WWAN (e.g., a long term evolution (LTE), universal telecommunications mobile system (UMTS), or similar transceiver) and another transceiver operable for communicating with the RAN of the WLAN (e.g., a WiFi transceiver). The UE may additionally or alternatively include a single transceiver operable for communicating with both RANs (e.g., WWAN and WLAN). In either case, the UE can aggregate communications over WWAN and WLAN connections at the RAN layer (e.g., at a media access control (MAC), packet data convergence protocol (PDCP) or similar layers, also known as “RAN aggregation”) to provide simultaneous access to one or more network nodes, to offload traffic from the WWAN to WLAN or vice versa, and/or the like.
In current implementations of RAN aggregation, an anchor node (e.g., an evolved Node B (eNB) at the WWAN) schedules downlink communications over the WWAN and WLAN connections for a given UE. For uplink communications, however, transmissions over the WLAN are typically not scheduled and occur opportunistically by the UE. This can impact synchronization in the WWAN that implements RAN aggregation over a WLAN connection (e.g., where packets are received out-of-order over the WLAN connection or otherwise not received within an expected receive window due to delay in transmission, or preemptive transmission, of packets over the WLAN connection).